Alkaline stress-induced apoptosis in human pulmonary artery endothelial cells.

The effect of alkaline stress, or an increase in extracellular pH (pHext), on cell viability is poorly defined. Human pulmonary artery endothelial cells (HPAEC) were subjected to alkaline stress using different methods of increasing pHext. Viability and mode of cell death following alkaline stress were determined by assessing nuclear morphology, ultrastructural features, and caspase-3 activity. Incubation of monolayers in media set to different pHext values (7.4-8.4) for 24-h induced morphological changes suggesting apoptosis (35-45% apoptotic cells) following severe alkaline stress. The magnitude of apoptosis was related to the severity of alkaline stress. These findings were confirmed with an assessment of ultrastructural changes and caspase-3 activation. While there was no difference in the intracellular calcium level ([Ca(2+)](i)) in monolayers set to pHext 7.4 versus 8.4 following the first hour of alkaline stress, blockade of calcium uptake with the chelator, EGTA, potentiated the magnitude of apoptosis under these conditions. Potentiation of apoptosis was reduced by calcium supplementation of the media. Finally, alkaline stress was associated with an increase in intracellular pH. This is the first report of apoptosis following alkaline stress in endothelial cells in the absence of other cell death stimuli.

Migratory pulmonary infiltrates in a patient with rheumatoid arthritis.

The case history is described of an elderly man with rheumatoid arthritis receiving treatment with sulfasalazine and the cyclooxygenase-2 inhibitor celecoxib who presented with severe shortness of breath, cough, and decreased exercise tolerance. The chest radiograph showed unilateral alveolo-interstitial infiltrates and a biopsy specimen of the lung parenchyma showed changes consistent with acute eosinophilic pneumonia. Antibiotic treatment was unsuccessful, but treatment with steroids and discontinuation of sulfasalazine and celecoxib resulted in a marked clinical improvement confirmed by arterial blood gas analysis. The condition may have developed as an adverse reaction either to sulfasalazine or to celecoxib, although hypersensitivity to the latter has not previously been reported.

Light microscopic and ultrastructural evidence of in vivo phagocytosis of Helicobacter pylori by neutrophils.

Helicobacter pylori is believed to cause chronic active gastritis. Infection/colonization of the gastric mucosal surface induces a mucosal inflammatory reaction in the form of lymphocytic aggregates, plasma cells and, particularly, neutrophils, which may, in turn, damage the mucosal epithelium. In vitro studies demonstrate that, in culture, the bacilli are readily phagocytosed by neutrophils, this evoking a neutrophilic oxidative burst. However, it has been claimed that neutrophils do not phagocytose H. pylori in vivo. In this study of 19 endoscopic biopsies of gastric mucosa with H. pylori-associated gastritis, Cresyl violet staining for light microscopy and electron microscopy are used to demonstrate that, in vivo, neutrophils actively phagocytose and destroy the bacilli in the epithelial intercellular space and in the mucin on the surface of the mucosa. Direct contact of neutrophils with H. pylori was observed in 17 of 17 cases by light microscopy and in 4 of 15 cases by electron microscopy. Phagocytosis by neutrophils was seen in 14 of 17 cases by light microscopy and in 3 of 1 5 cases by electron microscopy. It was most evident in the surface mucus coat where "wolf packs" of neutrophils were seen attacking the microbes. Ultrastructurally, neutrophil phagolysosomes contained both intact and partially digested bacteria, convincing evidence that the primary function of neutrophils in chronic active gastritis is to destroy H. pylori organisms. This study leaves open the question of whether, or how, neutrophils damage the gastric mucosa.

Composite keratohyaline granules in striate keratoderma.

The gross, light microscopic, and ultrastructural findings in a 55 year old man was striate keratoderma are presented. There was no family history of the disease. The lesions developed in his late teens and early adult years, and consisted of progressively worsening, raised, hyperkeratotic, linear plaques on the palm and volar surface of the third and fifth fingers bilaterally. There were also painful callosities on both heels, and thick, raised plaques on the heels and lateral plantar surfaces. The epidermis was papillomatous and acanthotic, with marked orthokeratosis, minimal parakeratosis, and a very thickened granular layer. No epidermolysis was seen. Electron microscopy showed increased tonofibrils in the stratum spinosum arranged in wavy, parallel bundles and a granular layer in which normal Odland bodies were present. However, the keratohyaline granules were large, with rounded borders and a striped, alternating, dark and light content characteristic of composite granules. There was diminished contact of the granules with tonofibrils. The transition to the stratum corneum was abrupt. The ultrastructural and genetic features of keratodermas, with special emphasis on the striate type, are reviewed.

Lung adenocarcinomas metastatic to the brain with and without ultrastructural evidence of rootlets: an electron microscopic and immunohistochemical study using cytokeratins 7 and 20 and villin.

Adenocarcinomas metastatic to brain from lung or colon may pose differentiation difficulties. Ultrastructurally, both may have brush borders with rootlets. This study examines the ultrastructural morphology and immunohistochemical expression of villin (associated with rootlets), cytokeratin 7 (present in lung adenocarcinomas), and cytokeratin 20 (present in colon adenocarcinomas) in 19 formalin-fixed sequential surgical biopsies of lung adenocarcinomas metastatic to brain as compared to 13 colonic adenocarcinoma metastases. Of lung tumor metastases, mucinous differentiation with rootlets was most common [6/19(32%)]. All colon tumor metastases were cytokeratin 7(-), 20(+), and profusely villin(+). Well-formed rootlets were seen. All lung metastases were cytokeratin 7(+) and 20(-). 5/6(83%) lung metastases with rootlets were focally villin(+). 12/13(95%) without rootlets were villin(-). Rootlets are extremely common in lung adenocarcinoma metastatic to brain. Villin immunoreactivity closely correlates with rootlets. Its distribution is a useful adjunct to cytokeratin 7 and 20 in differentiation of lung versus colon adenocarcinomas metastatic to the brain.

A histological, immunological, and electron microscopic study of bovine collagen implants in the human.

The histological fate of an injectable form of type I bovine dermal collagen (Zyderm collagen implant) in the human dermis and subcutaneous tissue has been studied. Sequential biopsies were analyzed by hematoxylin-eosin and Weigert's stains, by immunofluorescence (using a highly specific rabbit anti-Zyderm collagen antibody and a specific anti-human type III collagen antibody), and by electron miscroscopy. The results of this study suggest that the bovine implant material stimulates a host response resulting in implant degradation and replacement by newly generated host collagen.

The acquired immunodeficiency syndrome: an ultrastructural study.

Blood and a variety of tissues from 97 patients with the acquired immunodeficiency syndrome (AIDS) and 25 with the AIDS prodrome were studied ultrastructurally. Tubuloreticular structures (TRS) were found in 85 per cent of the patients with AIDS and in 92 per cent of those with the prodrome. Test tube and ring-shaped forms (TRF), found in 41 per cent of the patients with AIDS and in 8 per cent of those with the prodrome, increased with disease progression. Among the patients with AIDS, as the number of sites examined per case increased, the incidence of TRS and TRF tended to approach 100 per cent, suggesting that they are present in all patients with AIDS. Other changes seen frequently were immunologic capping of blood lymphocytes, intramitochondrial iron in blood reticulocytes and marrow normoblasts, megakaryocytic immaturity and platelet phagocytosis, collections of membranous rings in hepatocytic cytoplasm, suggestive of non-A, non-B hepatitis, and proliferations and engorgement of hepatic Ito cells with lipid. The data suggest that TRS and TRF can be used as diagnostic and prognostic markers.

Ultrastructural localization in the mouse lung of venom from the western diamondback (Crotalus atrox) rattlesnake.

Procedures which make immune complexes between venom antigens and their complementary antibodies visible have been applied to detect the site of deposition of rattlesnake venom in the lung tissue of mice after in vivo envenomation. Lung tissue, from mice envenomated with reconstituted but otherwise unmodified Crotalus atrox venom, was incubated in commercially available polyvalent antiserum (against North American crotalid snakes) which had been conjugated to the enzyme horseradish peroxidase. The enzyme reaction was developed for visualization by transmission electron microscopy. The enzyme reaction products were located along alveolar surfaces and were associated with multilamellar bodies in cytosomes of type II pulmonary epithelial cells. It was concluded that the venom has a specific affinity towards the extracellular surfactant in the lung and towards intracellular sites of surfactant synthesis.

Bovine collagen implant: histologic chronology in pig dermis.

The histologic fate of an injectable form of type I bovine dermal collagen (Zyderm Collagen Implant, ZCI) in the pig dermis and subcutaneous tissue has been studied. Biopsies were taken sequentially and analyzed by hematoxylin and eosin (H&E) and Weigert's stain, by birefringence, by direct immunofluorescence (using a highly specific rabbit anti-Zyderm antibody), and by electron microscopy. The implant material was found to stimulate a host response resulting in implant degradation and replacement by newly generated host collagen.

A scanning electron microscope study of normal and SV40-infected human keratinocytes.

We have studied the changes in the surface ultrastructure of human epidermal keratinocytes after infection by the oncogenic virus, SV40. The surfaces of uninfected cells show patterns of dense microvilli and microridges in varying proportion with microridges predominating in the center of the developing keratinocyte colony and on the fully mature keratinocytes (squames) and the microvilli being more prevalent on the immature proliferative cells at the colony periphery. As the transformation process progressed over time highly microridged surfaces became less numerous. After many months in culture cell surfaces were found to exhibit more sparse, predominantly villous ultrastructure. The surface characteristics of the infected cells in long term culture were similar to those observed in a cell line derived from a squamous cell carcinoma.